This study is a phase II (n= 200), prospective, double-blind, randomized, sham-controlled, multicenter, safety study of intravenous (IV) rt-PA alone versus IV rt-PA plus TLT (Transcranial Laser Therapy) at approximately 10 investigational sites (United States only). The primary endpoint for this safety study is occurrence of symptomatic intracranial hemorrhages at 36 - 48 hours after stroke symptom onset.